Abstract : Highlights of the IBM 4341 and the IBM 3033 AP systems are presented, with emphasis of performance aspects. An analysis of performance of the Virtual Machine Facility 370 (VM/370) is performed. The main efforts are: (1) to present a methodology based on performance measurement and analysis techniques, trying to relate the trends in the data to the characteristics of the system, and thus gain an insight into what might cause the system to saturate and its performance to degrade; (2) analyze the statistical correlations among performance and resource usage variables in order to estimate the degree of association among these variables; (3) identify those variables that are good indicators of system load; and (4) formulate regression equations for forecasting the system performance. This thesis is an effort toward the development of performance and resource usage forecasting equations, and a model for analyzing computer performance and resource allocation, of computer systems using VM/370. (Author)